Process for hydrotreating a diesel fuel feedstock, hydrotreating unit for the implementation of the said process, and corresponding hydrorefining unit

Abstract

The invention relates to a process for the catalytic hydrotreating of a feedstock of petroleum origin of diesel fuel type and of a feedstock of biological origin based on vegetable oils and/or animal fats in a stationary bed catalytic hydrotreating unit, the said process being characterized in that the feedstock of petroleum origin is introduced into the said reactor upstream of the feedstock of biological origin. It also relates to a catalytic hydrotreating unit for the implementation of the said process and to a corresponding hydrorefining unit.

The invention claimed is: 
     
       1. A process for the catalytic hydrotreating of a feedstock of petroleum origin of diesel fuel type and of a feedstock of biological origin based on vegetable oils and/or animal fats in a stationary bed hydrotreating unit, comprising the step of:
 introducing the feedstock of petroleum origin into the hydrotreating unit upstream of the feedstock of biological origin such that a hydrodeoxygenation of the feedstock of biological origin takes place downstream of a hydrodesulfurization of the feedstock of petroleum origin, and the level of the feedstock of biological origin based on vegetable oils and/or animal fats is up to 30% by weight. 
 
     
     
       2. The process according to  claim 1 , in which the step of introducing comprises the steps of:
 injecting the feedstock of petroleum origin into a first catalytic region of the hydrotreating unit; and 
 injecting the feedstock of biological origin into a second catalytic region of the hydrotreating unit situated downstream of the first catalytic region. 
 
     
     
       3. The process according to  claim 1 , in which the step of introducing comprises the steps of:
 injecting the feedstock of petroleum origin into a single reactor of the hydrotreating unit; and 
 injecting the feedstock of biological origin into the single reactor downstream of the feedstock of the petroleum origin. 
 
     
     
       4. The process according to  claim 1 , in which the step of introducing comprises the steps of:
 injecting the feedstock of petroleum origin into a first reactor of the hydrotreating unit; and 
 injecting a mixture of the feedstock of biological origin and liquid effluent exiting from the first reactor into a second reactor of the hydrotreating unit. 
 
     
     
       5. The process according to  claim 1 , in which the step of introducing comprises the steps of:
 injecting the feedstock of petroleum origin into a first reactor of the hydrotreating unit; 
 injecting a first part of the feedstock of biological origin into the first reactor of the hydrotreating unit; and 
 injecting a second part of the feedstock of biological origin and liquid effluent exiting from the first reactor into a second reactor of the hydrotreating unit. 
 
     
     
       6. The process according to  claim 1 ,  2 ,  3 ,  4  or  5 , in which the space velocity (HSV) of the feedstock of petroleum origin is less than the space velocity of the feedstock of biological origin, as a mixture with the effluent resulting from the treatment of the feedstock of petroleum origin. 
     
     
       7. The process according to  claim 1 , in which the feedstock of petroleum origin of diesel fuel type is chosen from the group consisting of
 i) diesel fuel fractions originating from a distillation of a crude oil and/or of a synthetic crude resulting from the treatment of oil shales of heavy and extraheavy crude oils, or of the effluent from a Fischer-Tropsch process, and 
 ii) diesel fuel fractions resulting from a conversion process, in which the conversion process is catalytic and/or thermal cracking. 
 
     
     
       8. The process according to  claim 1 , in which the level of the feedstock of biological origin is less than or equal to 15% by weight. 
     
     
       9. The process according to  claim 1 , in which the vegetable oils present in the feedstock of biological origin are chosen from the group consisting of palm oil, soybean oil, rapeseed oil, sunflower oil, linseed oil, rice bran oil, maize oil, olive oil, castor oil, sesame oil, pine oil, peanut oil, palm kernel oil, coconut oil, babasu oil, and a mixture of two or more of these oils. 
     
     
       10. The process according to  claim 2 , in which the catalytic region for the injection of the feedstock of biological origin comprises a first metal trap catalytic bed. 
     
     
       11. The process according to  claim 2 , further comprising:
 introducing hydrogen into the first catalytic region, in which the amount of hydrogen introduced into the first catalytic region is from 50 to 1000 Normal liters of H 2  per liter of the feedstock of petroleum origin. 
 
     
     
       12. The process according to  claim 2 , further comprising:
 introducing hydrogen into the second catalytic region, in which the amount of hydrogen introduced into the second catalytic region is from 50 to 2000 Normal liters of H 2  per liter of total feedstock, and the total feedstock is the feedstock of biological origin, as a mixture with the effluent resulting from the treatment of the feedstock of petroleum origin. 
 
     
     
       13. The process according to  claim 2 , in which the temperature of the first catalytic region for treatment of the feedstock of petroleum origin is from 320 to 420° C. 
     
     
       14. The process according to  claim 2 , in which the temperature of the second catalytic region for treatment of the feedstock of biological origin, as a mixture with the effluent resulting from the treatment of the feedstock of petroleum origin, is from 250 to 420° C. 
     
     
       15. The process according to  claim 1 , in which the feedstocks are treated at a pressure of 25 to 150 bar. 
     
     
       16. The process according to  claim 2 , in which the HSV of the feedstock of petroleum origin in the first catalytic region is from 0.3 to 5. 
     
     
       17. The process according to  claim 2 , in which the HSV in the second catalytic region of total feedstock is from 0.5 to 10, and the total feedstock is the feedstock of biological origin, as a mixture with effluent resulting from the treatment of the feedstock of petroleum origin. 
     
     
       18. The process according to  claim 1 , further comprising:
 passing the feedstock of biological origin through at least one catalytic bed in the hydrotreating unit, 
 in which the catalytic bed comprises a catalyst based on metal oxides chosen from the group consisting of oxides of metals from Groups VI-B and VIII-B supported on a support chosen from the group consisting of alumina, silica/alumina, zeolite, ferrierite, phosphated alumina, phosphated silica/alumina, and a mixture of two or more of these. 
 
     
     
       19. The process according to  claim 1 , in which the feedstock of biological origin introduced into the hydrotreating unit is treated over at least one catalytic bed at least partially comprising a catalyst with an isomerizing role on an acidic support. 
     
     
       20. The process according to  claim 1 , further comprising:
 injecting water in the region for treatment of the feedstock of biological origin. 
 
     
     
       21. The process according to  claim 1 , further comprising:
 treating recycle gas resulting from the hydrotreating of total feedstock before it is reinjected into the hydrotreating unit; and 
 separating and treating the carbon monoxide (CO) present in the recycle gas before the recycle gas is reinjected into the hydrotreating unit. 
 
     
     
       22. The process according to  claim 21 , in which the step of separating and treating CO is carried out by means of a CO conversion unit using the CO shift reaction. 
     
     
       23. The process according to  claim 21 , in which the step of separating and treating CO is carried out by means of a Pressure Swing Adsorption (PSA) treatment unit. 
     
     
       24. The process according to  claim 2 , further comprising:
 using the separated CO in a steam methane reformer (SMR). 
 
     
     
       25. The process according to  claim 1 , further comprising:
 treating recycle gas resulting from the hydrotreating of total feedstock before it is reinjected into the hydrotreating unit, 
 separating and treating the carbon dioxide (CO 2 ) and the hydrogen sulphide (H 2 S) present in the recycle gas before the recycle gas is reinjected into the hydrotreating unit. 
 
     
     
       26. The process according to  claim 1 , in which the exothermicity of the hydrotreating of the feedstock of biological origin is controlled by means of temperature control systems. 
     
     
       27. The process according to  claim 26 , further comprising:
 adding a liquid in the region of treatment of the feedstock of biological origin. 
 
     
     
       28. The process according to  claim 27 , further comprising:
 injecting the feedstock of petroleum origin into a first reactor of the hydrotreating unit; 
 recovering heat from effluent exiting from the first reactor; 
 lowering the temperature of the effluent before it is injected into a second reactor of the hydrotreating unit; and 
 injecting the feedstock of biological origin and the effluent exiting from the first reactor into the second reactor of the hydrotreating unit. 
 
     
     
       29. The process  claim 1 , in which the hydrotreating unit operates as a single-pass unit, without recycling of liquid effluent at the top of the hydrotreating unit. 
     
     
       30. The process according to  claim 7 , in which the conversion process is Fluidized Catalytic Cracking (FCC), coking, or visbreaking. 
     
     
       31. The process according to  claim 9 , in which one of the vegetable oils is palm oil. 
     
     
       32. The process according to  claim 11 , in which the amount of hydrogen introduced into the first catalytic region is from 100 to 500 Normal liters of H 2  per liter of the feedstock of petroleum origin. 
     
     
       33. The process according to  claim 11 , in which the amount of hydrogen introduced into the first catalytic region is from 120 to 450 Normal liters of H 2  per liter of the feedstock of petroleum origin. 
     
     
       34. The process according to  claim 12 , in which the amount of hydrogen introduced into the second catalytic region is from 150 to 1500 Normal liters of H 2  per liter of the total feedstock. 
     
     
       35. The process according to  claim 12 , in which the amount of hydrogen introduced into the second catalytic region is from 200 to 1000 Normal liters of H 2  per liter of the total feedstock. 
     
     
       36. The process according to  claim 13 , in which the temperature of the first catalytic region for treatment of the feedstock of petroleum origin is from 340 to 400° C. 
     
     
       37. The process according to  claim 14 , in which the temperature of the second catalytic region for treatment of the feedstock of biological origin, as a mixture with the effluent resulting from the treatment of the feedstock of petroleum origin, is from 280 to 350° C. 
     
     
       38. The process according to  claim 15 , in which the feedstocks are treated at a pressure of 30 to 70 bar. 
     
     
       39. The process according to  claim 16 , in which the HSV of the feedstock of petroleum origin in the first catalytic region is from 0.6 to 3. 
     
     
       40. The process according to  claim 17 , in which the HSV of the total feedback in the second catalytic region is from 1 to 5. 
     
     
       41. The process according to  claim 18 , in which the metal oxides are chosen from the group consisting of oxides of metals from Mo, W, Co, Ni, Pt, Pd, Ru, Rh and mixtures of two or more of these. 
     
     
       42. The process according to  claim 18 , in which the metal oxides are chosen from the group consisting of NiMo, CoMo, NiW, PtPd and mixtures of two or more of these. 
     
     
       43. The process according to  claim 19 , in which the catalyst is based on nickel oxides, and the acidic support is chosen from the group consisting of amorphous silica/alumina, zeolite, ferrierite, phosphated alumina, and phosphated silica/alumina. 
     
     
       44. The process according to  claim 23 , further comprising:
 separating and treating at least one of methane (CH 4 ), ethane (C 2 H 6 ), and propane (C 3 H 8 ) gases present in the recycle gas by means of a PSA treatment unit before the recycle gas is reinjected into the hydrotreating unit. 
 
     
     
       45. The process according to  claim 43 , further comprising:
 using the separated methane (CH 4 ), ethane (C 2 H 6 ), or propane (C 3 H 8 ) gas in a SMR. 
 
     
     
       46. The process according to  claim 27 , further comprising:
 injecting the feedstock of petroleum origin into a first reactor of the hydrotreating unit; 
 injecting a first part of the feedstock of biological origin into the first reactor of the hydrotreating unit; 
 recovering heat from effluent exiting from the first reactor; 
 lowering the temperature of the effluent before it is injected into a second reactor of the hydrotreating unit; and 
 injecting a second part of the feedstock of biological origin and the effluent exiting from the first reactor into the second reactor of the hydrotreating unit.